What is the surgical technique of core decompression for avascular necrosis?

Core Decompression Surgical Technique for Avascular Necrosis

Core decompression is an effective joint-preserving procedure for early-stage avascular necrosis of the femoral head, with success rates of 84% for Steinberg stage I, significantly outperforming conservative management. 1

Surgical Technique

Traditional Single-Tunnel Technique

• The procedure begins with positioning the patient supine on the operating table 2
• An incision is made parallel to the lateral cortex of the proximal femur, just below the greater trochanter 3
• An 8-mm cannulated drill bit or Michele trephine is inserted from the lateral cortex of the proximal femur 2, 3
• The drill is directed into the center of the necrotic lesion to within 5mm of the articular surface 3
• Two additional smaller trephine tracts (5-6mm) may be created to enhance decompression 3

Multiple Small-Drilling Technique

• This less invasive alternative uses multiple smaller drill holes instead of a single large tunnel 2
• The technique aims to decrease the risk of postoperative fracture while maintaining decompression effectiveness 2

Bone Grafting

• Cancellous bone recovered from the intertrochanteric region can be thinned with a rongeur 3
• This autologous bone is placed loosely into the central decompression channel to serve as a graft 3
• Alternatively, synthetic bone-graft substitutes with osteoinductive properties may be used to fill the void 4

Preoperative Planning

• CT imaging is essential for surgical planning, showing the precise location and extent of the necrotic lesion 5
• The necrotic volume is a critical factor in predicting outcomes - lesions involving <30% of the femoral head have <5% progression to collapse 6, 5
• 3D-printed guide plates can improve surgical precision and decrease operative time 5

Adjunctive Techniques

• The core decompression procedure can be supplemented with various adjunctive therapeutics: 2
  • Tantalum rod insertion for structural support
  • Orthobiologics including bone marrow aspirate concentrate, mesenchymal stem cells, or platelet-rich plasma
  • Electric stimulation to promote healing

Postoperative Management

• Protected weight-bearing is recommended following the procedure to prevent fracture 5
• Regular radiographic follow-up is essential to monitor for disease progression or femoral head collapse 5
• Supplementation with vitamins and minerals may be considered to support bone mineralization during healing 7

Outcomes and Considerations

• Success rates are significantly better for early-stage disease (Stages I and II) compared to advanced stages 3
• Defect size is a critical factor - smaller lesions have significantly lower rates of femoral head collapse 4
• The procedure carries a small risk of complications including subcapital fracture, pulmonary embolism, and infection 3
• For late-stage femoral head osteonecrosis with articular collapse, more definitive procedures like hemiarthroplasty or total joint arthroplasty may be necessary 6

Pitfalls to Avoid

• Avoid drilling too close to the articular surface (maintain at least 5mm distance) to prevent iatrogenic fracture 3
• Ensure proper trajectory of the drill to target the necrotic lesion accurately, using imaging guidance when available 2
• Be cautious with patient selection - outcomes are significantly better for smaller lesions and earlier disease stages 4, 1